The mechanisms controlling human placental GH and CS gene activation and repression in placenta will be investigated. In the proposed studies, the following aims will be pursued: 1) the individual enhansons characterizing the enhancer will be investigated; 2) multiple enhancer interactions will be characterized in placental and pituitary cells; 3) the relationship of the enhancer interactions with pituitary-specific P element repressors will be investigated; 4) the chromatin structure and matrix attachment regions in the CS/GH locus will be defined; and 5) enhancer (CSEF-1) and inhibitor (CSInrF) proteins will be isolated, sequenced, and cloned.